Ore-crusher



J1. G. WISWELL.

` @RE GRUSHER.

(N0 Model.)

No. 307,513e` f Innen/:bo 7" "rares ORE-CRUSHER.

SPECIFICATION forming part of Letters Patent No, 307,513, datedNovember 4, 1834. .Application filed May 28, 1894. (No model.)

To all whom t may concern:

Be it known that I, LMoon CHAnLns Wis WELL, of Medford, in the county of Middlesex and State of Massachusetts, haveinvented 4certain Improvements in Ore-Crushers, `of

' granted to me April l, 1884:.

My present invention consists wholly in the improvements in the form of the, peripheries of the rollers, and of the corresponding portion of the circular bed, hereinafter described, whereby the meetingpoint of the outer faces of the rollers with the bed is enabled to extend entirely across said faces, and the rollers are enabled to travel easily and with the minimum of friction upon the portions of the bed supporting their outer faces, as I will now proceed to describe.

Of the accompanying drawings, forming a part of this specification, Figure l represents a plan view of a series of rollers and their supporting-bed embodying my improvements. Fig. 2 represents a section on line x m, Fig. 1.

rlhe same letters of reference indicate the same parts in all the figures.

In the drawings, a a a a represent the series of crushingrollers, which are in this instance four in number, and are mounted on radial axlesb, which are journaled in aframe, c, substantially as shown in my above-named patent, said frame being affixed horizontally to a vertical shaft, d, which is supported at its lower end by a step, e, and is rotated by power suitably applied to its upper end.. rIhe periphery of each roller is composed of two inclined or beveled faces, 2 3, which are arranged to give said periphery a pyramidal.

form in its transverse section. rlhe inner face, 2, of each roller is a conic frusturn, of which the apex is the intersection of the axial line of the vertical shaft d and of the axial line of the axles of the rollers, as shown in dotted 'lines in Fig. l. Owing to this form, the periphery of the inner face of the roller adapts itself naturally to the correspondingly-formed bed,

lthe following rules must hereinafter described, and traverses the latter with ease, free from slip and lost motion, which reduces the friction to the minimum. The outer face, 3, of each roller in any portion of its transverse section presents an arc of a circle having a radius of the same length as the radius of the circle formed by the outer margin of the supporting-bed h, on which the rollers travel, the opposite arcs being struck from separate centers.

In forming the outer face, 3, of each roller be followed: First, the diameter of the roller at the apex of its periphery must be about equal to the radius of the circle formed by the outer margin of the supporting-bed; secondly, the distance of the apex of' the periphery of the roller from the center of the shaft d having been determined, the centers @""j of the arcs ivlf and j j,

which the cross-section of the outer face, 3, of the roller presents, are located by finding the points where lines 7c k, of the same length as the radius above mentioned, drawn from the apex of the periphery of the roller, intersect lines Z Z, drawn from the peripheries of the two adjacent rollers to the center of the shaft d. The circular supporting bed or trough lt has two faces, 2 3, which are so formed that the cross-section of the bed presents the exact converseof the cross-section of each roller, as shown in Fig. 2, the line of contact of each roller with the bed extending entirely across both faces of the roller, as shown.

The above-described form of the inner faces of the rollers and of the supporting-bed is fully set forth in my former patent, the novelty now presented being the form of the outer faces 3, of the rollers and of the faces 3 of the bed. I have found by practical experience that the described form of the faces Sand 3 enables the rollers to run freely and naturally in a circular direction7 the outer face of each roller crushing equally with the inner faces, because of their extended bearing on the bed. The rollers rotate and travel without greater friction between the outer faces, 3 and 3', than between the faces 2 and 2', and therefore without torsional or binding strain upon their axles. Heretoforein mills of this class theouter faces of the rollers have generally been cone-frustums, presenting straight sur faces in cross-section, likethe inner faces. If

A said faces fitted snugly to the outer faces of the trough, an abrasive action would ensue between the two, as stated in my former patent, the friction attending the movement of the outer faces of the rollers being greater than that attending the movement of the inner faces; hence the outer faces of the rollers had to be slightly separated from the corresponding face of the bed. This objection and the necessity of such separation is entirely-overcome by the present improvement, which ef fects a considerable saving in motive power,

` and largely increases the capacity of the mill for work,in consequence of the increased area of crushing-surface and the facility which the described peculiarities of form of rollers and bed afford in aiding the discharge of the pulverized ore from the screen. Said ore is thrown upward and outward by centrifugal force of the revolving rollers, and escapes through a screen or screens in the curb z, surrounding the bed or trough, as described in my former patent. Suitable' openings are formed at the bottom of the bed or trough to permit the drawing off of the amalgam and materials used in cleaning the trough.

It is obvious that one roll may be Vemployed instead of a series without departing from the spirit of my invention.

I claim- A crushing-roller adapted to travel in a circular path, and having the inner crushingface, 2, which isa cone-frustum having its apex in the center of the circular path in which the rolls travel, and the outer crushing-face, 3, which presents in cross-section the arc of a circle having the described radius,the opposite arcs having different radial centers, combined with the bed or trough formed to present in cross-section the exact converse of the crosssection of the roller, whereby an extended bearing between the roller and bed is afforded, and the roller is enabled to travel easily and with the minimum of friction, as set forth.

In testimony whereof I have signed my-name to this specication, in the presence of two subscribing witnesses, this 17th day of May, 188,4.

J AGOB C. WISWELL. Vitn esses':

C. F. BROWN, A. L. WHITE. 

